Ferrous sulfate heptahydrate CAS37782-63-0
Ferrous sulfate has the chemical formula FeSO₄. Its most common commercial form is ferrous sulfate heptahydrate FeSO₄·7H₂O, widely known as green vitriol. It appears as light blue‑green monoclinic crystals with a density of 1.898 g/cm³. It melts within its crystal water at 64 °C, and its aqueous solution shows acidic properties. The substance gradually effloresces when exposed to air and gets oxidized into yellow‑brown iron salts. It loses all crystal water at 300 °C, turning into a white powdery solid.
Ferrous sulfate is susceptible to oxidation, turning yellow or rust‑colored under humid atmospheric conditions. It dissolves readily in water; typical working solution concentration is around 10%. Used as a coagulant, it generates large floc particles with excellent settling behavior and remarkable decolorizing capacity. Featuring low reagent cost, it is well‑suited for wastewater treatment systems operating at pH above 8.5.
Ferrous sulfate heptahydrate Chemical Properties
| Melting point | 64 °C |
| density | 1.898 g/mL at 25 °C (lit.) |
| vapor pressure | 14.6 mm Hg ( 25 °C) |
| storage temp. | Store at +15°C to +25°C. |
| solubility | 25.6 g/100 mL (20°C) |
| form | Solution |
| color | Slightly greenish to blue |
| Specific Gravity | 1.898 |
| PH | 3.0-4.0 (25℃, 50mg/mL in H2O) |
| Odor | pale bluish-grn. cryst. or gran., odorless |
| Water Solubility | 25.6 g/100 mL (20 ºC) |
| Sensitive | Air Sensitive & Hygroscopic |
| Merck | 14,4057 |
| Exposure limits | ACGIH: TWA 1 mg/m3 NIOSH: TWA 1 mg/m3 |
| Stability: | Stable. Substances to be avoided include strong oxidizing agents. Air and moisture sensitive. |
| InChIKey | SURQXAFEQWPFPV-UHFFFAOYSA-L |
| LogP | -1.031 (est) |
| CAS DataBase Reference | 7782-63-0(CAS DataBase Reference) |
| EPA Substance Registry System | Ferrous sulfate heptahydrate (7782-63-0) |
